Water Supply Engineering: Introduction

 Lecture - 01

Water

ü Water is essential for all forms of life.

ü Used for:

·         Drinking

·         Cooking and food preparation

·         Sanitation and hygiene

·         Irrigation and agriculture

·         Industrial and manufacturing processes

·         Energy production (e.g., hydroelectric power)

Availability of Water on Earth

• 71% of Earth’s surface is covered by water.
• Only 2.5% of the total water is freshwater.
• Less than 1% of freshwater is accessible (in rivers, lakes, shallow groundwater).

Global Water Distribution and Scarcity

• Freshwater resources are unevenly distributed.
• Many regions face seasonal or chronic water shortages.
• More than 2.2 billion people worldwide lack safely managed drinking water.

Major Challenges in Water Supply

·         Scarcity of freshwater due to:

o    Climate change

o    Overuse of groundwater

o    Uneven distribution

·         Pollution from industrial, agricultural, and domestic sources

·         Rapid urbanization and increasing demand

·         Aging or inadequate infrastructure

·         Poor water management practices

Water Use by Sector

·         Agriculture: ~70% of global freshwater use

·         Industry: ~20%

·         Domestic use: ~10%

Solutions to Water Challenges

·         Integrated Water Resources Management (IWRM)

·         Investment in water infrastructure and sanitation

·         Protection of water sources

·         Public awareness and conservation practices

·         International cooperation and policy reform

Key Points

• Water is vital but limited and under threat.
• Safe and equitable access to water is a major global issue.
• Sustainable management of water resources is essential for future development.

References

• UN-Water. (2023). Water Facts. Retrieved from https://www.unwater.org
• WHO & UNICEF. (2023). Progress on household drinking water, sanitation and hygiene 2000–2022. Retrieved from https://washdata.org
• FAO. (2021). The State of the World's Land and Water Resources for Food and Agriculture. Retrieved from https://www.fao.org

 

Water Facts [United Nations, UN Water]

·        2.2 billion people (1 in 4) still live without safely managed drinking water, including 115 million people who drink surface water. (WHO/UNICEF, 2023).

 

·        3.5 billion people (4 in 10) still live without safely managed sanitation, including 419 million who practice open defecation. (WHO/UNICEF, 2023).

·        2 billion people still lack basic hygiene services, including 653 million with no facility at all. (WHO/UNICEF, 2023).

·        Around 1,000 daily deaths of children under five are due to unsafe water, sanitation and hygiene. (WHO, 2023)

·        Children under the age of 15 living in countries affected by protracted conflict are, on average, almost three times more likely to die from diarrhoeal diseases caused by a lack of safe water, sanitation and hygiene than by direct violence. (UNICEF, 2019)

·        More than 2 billion people live in countries under water stress and 3.6 billion face inadequate access to water at least one month per year. (WMO, 2021)

·        Water-related disasters account for 70% of all disaster related deaths. (World Bank Group, 2022)

·        Since 2000, flood-related disasters have increased by 134%. (WMO, 2021)

·        In 2023, glaciers lost more than 600 gigatons of water, the largest mass loss registered in the last five decades. (WMO, 2024)

 

·        Only 0.5% of water on Earth is useable and available freshwater. (WMO, 2021)

·        To meet SDG 6, progress needs to increase, on average, by 6x for safely managed drinking water, 5x for safely managed sanitation and 3x for basic hygiene. (WHO/UNICEF, 2023)

·        72% of all freshwater withdrawals are used by agriculture, 16% by industries, and 12% by municipalities. (FAO, 2023)

·        Global water demand is projected to increase by 20 to 30% by 2050. (UN, 2018)

·        To produce a person’s daily food, it takes 2,000-5,000 litres of water. A 50% increase in food demand is expected by 2050. (FAO, 2020)

·        Water-use efficiency has increased by 19.3% globally from 2015 to 2021, but around 58% of countries still exhibit low water-use efficiency. (FAO, 2024)

·        The world will not achieve sustainable water management until 2049. (UNEP, 2024)

·        Only 27% of industrial wastewater is safely treated. (UN-Habitat, WHO, 2024)

·        42% of household wastewater is not safely treated. (UN-Habitat, WHO, 2024)

·        Only 56% of monitored water bodies in 120 reporting countries are in “good ambient water quality”. (UNEP, 2024)

·        Just 43 out of 153 countries sharing transboundary waters have operational arrangements covering 90% or more of their shared water bodies. (UNECE, UNESCO, 2024)

·        Every US$ 1 invested in water and sanitation yields a return of US$ 4.3. (UN-Water GLAAS, 2014)

·        Aid for water and sanitation decreased by 5% between 2015 and 2022. (UN-Water GLAAS, 2022).

·        Estimates indicate that to achieve SDG 6, over US$1 trillion will be needed per year. (World Resources Institute, 2020).

 

SDG

Goal 6: Ensure availability and sustainable management of water and sanitation for all

Target 6.1:

Achieve universal and equitable access to safe and affordable drinking water for all

·        Indicator 6.1.1: Proportion of population using safely managed drinking water services

• Definition:
• Safely managed = Water from an improved source (piped water, boreholes, protected wells) that is:
• Accessible on premises.
• Available when needed.
• Free from contamination (E. coli, arsenic, fluoride, etc.).

 

Target 6.2:

Achieve access to adequate and equitable sanitation and hygiene for all and end open defecation, paying special attention to the needs of women and girls and those in vulnerable situations

• Indicator 6.2.1: Proportion of population using (a) safely managed sanitation services and (b) a hand-washing facility with soap and water
• Definition:
• Safely managed sanitation = Improved toilets (sewers, septic tanks) that:
• Are not shared.
• Treat/dispose waste safely.
• Basic handwashing = Soap and water available at home.

 

Target 6.3: 

Improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally

• Indicator 6.3.1: Proportion of domestic and industrial wastewater flows safely treated
• Definition:
• Domestic + industrial wastewater treated to meet standards.
• Measurement:
• National wastewater treatment reports.
• Challenges:
• High costs of treatment plants.

• Indicator 6.3.2: Proportion of bodies of water with good ambient water quality
• Definition:
• Rivers/lakes with low pollutants.
• Measurement:
• Water quality monitoring stations.
• Challenges:
• Agricultural runoff (fertilizers, pesticides).

 

Target 6.4: 

Substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity

• Indicator 6.4.1: Change in water-use efficiency over time
• Definition:
• GDP per unit of water used (economic efficiency).
• Measurement:
• National water withdrawal vs. economic output data.

• Indicator 6.4.2: Level of water stress: freshwater withdrawal as a proportion of available freshwater resources
• Definition:
• Freshwater withdrawn as % of available supply.
• High stress = >70% withdrawal (e.g., Middle East, India).
• Challenges:
• Overuse in agriculture (70% global withdrawals).

 

Target 6.5: 

Implement integrated water resources management at all levels, including through transboundary cooperation as appropriate

• Indicator 6.5.1: Degree of integrated water resources management
• Definition:
• Policies, funding, and stakeholder involvement in water management.
• Measurement:
• UNEP surveys scoring countries (0–100).

• Indicator 6.5.2: Proportion of transboundary basin area with an operational arrangement for water cooperation
• Definition:
• % of shared river/lake basins with joint management agreements.
• Challenges:
• Political conflicts over water (e.g., Nile River disputes).

 

Target 6.6: 

Protect and restore water-related ecosystems, including mountains, forests, wetlands, rivers, aquifers and lakes

• Indicator 6.6.1: Change in the extent of water-related ecosystems over time
• Definition:
• Satellite tracking of wetlands, mangroves, etc.
• Measurement:
• UNEP’s Global Wetland Outlook.
• Challenges:
• Wetlands lost 3x faster than forests.

Target 6.a:

Expand international cooperation and capacity-building support to developing countries in water- and sanitation-related activities and programmes, including water harvesting, desalination, water efficiency, wastewater treatment, recycling and reuse technologies

• Indicator 6.a.1: Amount of water- and sanitation-related official development assistance that is part of a government-coordinated spending plan
• Definition:
• Funds for water projects aligned with national plans.
• Challenges:
• Funding gaps (estimated $114B/year needed).

 

Target 6.b:

Support and strengthen the participation of local communities in improving water and sanitation management

• Indicator 6.b.1: Proportion of local administrative units with established and operational policies and procedures for participation of local communities in water and sanitation management
• Definition:
• % of villages/towns involving citizens in decisions.
• Challenges:
• Lack of grassroots governance.

 

Key Global Challenges for SDG 6:

• 2.2 billion lack safe drinking water (WHO, 2023).
• 3.5 billion lack safe sanitation (UNICEF, 2022).
• 80% of wastewater is untreated (UN Water).

 

Assignment:

Prepare a Report on ‘SDG 6 in Bangladesh: Current Status, Key Challenges, and Pathways to Ensure Clean Water and Sanitation for All’.